SYNTHESIS AND CHARACTERIZATION OF NATURAL MALIC ACID BASED LOW TRANSITION TEMPERATURE MIXTURES FOR BIOMASS DELIGNIFICATION.

Low transition temperature mixtures (LTTMs) derived from malic acid tend to be
the promising green solvents for effective dissociation of lignocellulosic biomass. In
this study, the optimum conditions for the microwave hydrothermal extraction of
malic acids from plants and fruits such as cactus, papaya, luffa cylindrica and
lophafherum herb are found to be at 1 g of sample, 200 °C and45 min in the presence
of hydrogen peroxide (H202) as oxidant. The extractions showed goodfitting with the
saturation equation model for the mass of extracted malic acid over dry weight of
sample below 100 mg/g. Cheap commercially available materials (sucrose and MSG)
were proven to be compatible as hydrogen bond acceptor (HBA) with L-malic acid as
hydrogen bond donor (HBD) in the preparation of LTTMs. The temperature and time
taken for the preparation of LTTMs without addition of water: sucrose (90 °C, 10
min) and MSG (110 °C, 30 min). Addition of water had reduced the temperature for
the preparation of LTTMs from sucrose and MSG to 60 °C and 90 °C while the
reaction time was shorten to 5 min and 15 min respectively.